Valve for rock drills



Jan. 24, 1933. I FEUCHT' 1,895,153-

VALVE FOR ROCK DRILLS Filed Sept. 7. 1952 ALEEET Five/4f INVENTOR wawATTORNEY Patented Jan. 24, 1933 UNITED STATES PATENT oFFicE ALBERTrnuonr, or CLEVELAND, oHIo, .Assrenoa TO THE CLEVELANDROCK DRILLooMPAiImor CLEVELAND, OHIO, A CORPORATION or OHIO VALVE FOB ROCK DRILLSApplication filed September This invention relates broadly to rockdrills, but more particularly to valvular mechanism therefor.

The object of this invention is to produce a rock drill with anefiicient valve for controlling the admission and partly the exhaust ofthe pressure fluid into and from the cylinder to actuate the workingpiston.

Other objects of this invention will be apparent from the followingdestailed descrip tion wherein similar characters of reference designatecorresponding parts and wherein:

Fig. 1 is a longitudinal sectional view of a portion of a rock drillillustrating the invention.

Fig. 2 and Fig. 3 are enlarged sectional views illustrating the valveand-piston in different positions.

The embodiment of the invention chosen for the purpose of illustrationcomprises a cylinder 10 formed with a piston chamber 11. Reoiprocablymounted within the chamber 11, there is a piston 12 formed with a stem13. The stem is manufactured with two annular recesses 14 and 15, thepurpose of which will be explained later. Secured in.pressed fitengagement within the front end of the cylinder, there is a tappetbushing 16 having a tappet 17 slidable therein. The tappet 1 PI'OJBCt-Sinto the cylinder chamber 10 to receive the impacts of the piston 12.The other end of the tappet is capable of engagement. with a workingimplement to transmit the blows of the piston in the usual manner.Toward the front the piston chamber 11 is connected to the atmospherethrough an exhaust passage 18.

Secured within the rear end of the cylinder 10, there is a valve block19 formed with a plurality of differential bores 20, 21, and 22. Thebores 20 and 22 are accurately machined to receive in pressed fitengagement there with a valve cap '23 formed with a central bore 24.Intermediate the valve block 19 and valve cap 23, there is formed avalve chamber 25, having a sleeve valve 26 reciprocably mounted therein.Intermediate its ends, the valve 26 is formed with an annular. recess27. The bottomof the bore 21 is terminated by an annular groove 28within 7, 19a2. Serial 170.631 ,981.

there is an annular groove 31 in communication with the rear end of thepiston chamber 11 through a plurality of passages 32. Adjacent to thegroove 31, there is .a similar groove 33 in communication with theatmosphere through a plurality of ports 34, external groove 35 andexhaust passage 36. The bottom of the valve block bore 20 is also inconstant communication with the atmosphere through a restricted venthole 37 opening into the exhaustpassage 36. Transversally' disposedthroughthe valve 26, thereis a restricted orifice :38 capable ofcommunication with the atmosphere through a vent hole 39. Leading fromthe valve cap bore24 into the valve chamber25, there is akick port 40.Formed intermediate the ends of the valve cap bore 24, there is anenlarged annular groove 41 capable of communication with the front endofthe piston chamber 11, through a plurality of passages 42, ,and'44.

The machine is terminated by a backhead 45 having a throttle 46rotatably mounted therein. The throttle valveis conveniently machinedwith a bore 47 within which pressure may be admitted from'any desirablesource. The backhead is formed with an enlarged reservoir 48 openingintothe valve cap bore 24; Pressure fiuidfrom the throttle valve bore 47maybe admitted into the reservoir 48 through a throttle valve passage 49and port 50. Leading from the reservoir 48 into the valve block groove28, there is a plurality of passages 41 and 52. p

In the operation'of the machine,assuming the parts to be positioned asillustratedin Fig. 2, pressure fiuid from the reservoir 48 is admittedinto the front end of the-piston,

chamber 11 throughthe valve cap bore 24, passages 42 and .44,thuscreating pressure upon the frontendof the piston '12 to move thesame rearwardly against the constant pressure exerted upon the end ofthe stem 13 passages 51 and 52 to act on the frontend of the valve. 26,hereafter denoted as restricted pressure area, tending to shift thevalve rear- Wardly. This last area be ng smaller than the area 43, thevalve 26 will remainin its forward position. During the rearwardmovement of the piston 12, the atmosphere or the pressure fluidremaining in the rear end of thepiston chamber 11 being compressed bythe piston, will exhaust to atmosphere through the passages32, annulargrooves 31, 27, and 33, ports 34, recess 35 and exhaust passage 36. Thusthe piston is free to move rearwardly as long as the valve 26 is in itsforward position as illustrated in Fig. 2. The piston continuing itsrearward travel will cover the groove 41, thus shutting off the flow ofthe pressure fluid into the front end ofthe piston chamber. Subsequentlythe exhaust passage 18 will be uncovered by the piston 12 allowing thepressure fluid in the front end of the pistonjchamber 11 to escape toatmosphere. Howeverthe piston carried by its momentum will continue tomove rearwardly until the recess 14 of the stem 13 is positioned toafford the communication of the kick port 4O -with the groove 41.- Atthat time, the pressure fluid acting onthe enlarged valve shifting area43 will. suddenly escape to atmosphere through the kick :port 40-,recess 14, groove 41, passages 42 and 44, and exhaust passage 18. Thearea of restricted orifices 30 supplying pressure fluidto the enlargedvalveshifting area 43, being smaller than the area of the kick port 40,will cause the pressure onthe area 4am drop. The

restrictedvalve shifting areabeing constantly subjected to the pressurefluid in the groove 28 will cause the shifting of the valve in the rearposition as illustrated-in Fig. 3; lVith the valve in that position,pressure fluid will flow from the groove 28 through the passages 29 andthe recess'15 of the stem 13 into the rear end of the piston chamber 11.to drive the piston forwardly for delivering its blow to the tappet 17.During the forward movement of the piston 12, the valve 26 is maintainedin its rearward position by the. pressure fluid acting onthe front endof the valve or on the valve 7 restricted pressure area. The pressureflu d remaining 011 the valve enlarged pressure area 43 is free toexhaust to the atmosphere through the restricted orifices 38, and ventlythe restricted orifice 3O andthe exhaust passages 32 and groove 31 arealso closed by the valve. The pressure fluid will flow into the rear endof the piston chamber 11 until the recess 15 of the piston stem 13 movesout of communication withthe ports 29. Toward the end of its forwardstroke, the pis ton 12 will uncover the exhaust passage 18,

allowing a portion of the pressure fluid into the rear of the pistonchamber 11 to exhaustto atmosphere. Simultaneously, the end of the stem13 will uncover the kick port 40 admitting the pressure fluid on theenlarged forwardly, the bottom of the valve block bore 2(l'beingconstantly vented to the atmosphere through the vent hole 37. Thus thepressure valve shifting area 43 to shift the valve 26 r may again beadmitted into the forward end of the piston chamber 11 as previouslyexplained' formed with a piston chamber, a piston. re-

ciprocably mounted within said piston chainber, said. piston having astem extending I Although the foregoing description is nec' therefrom, avalve block within'said cylinder formed with a bore within which saidstem is reciprocably guided, a valve within said valve block havingopposed enlarged and restricted pressure areas subjected to the pressurefluid for shifting and holding said valve in opposite directions, fluidconveying passages opened by said valve for allowing the admission ofthe pressure fluid into the rear end of said piston chamber to drivesaid piston forwardly, said'fluid conveying passages being subsequentlyclosed by said stem to terminate said admission, fluid conveying portsopened by said valvefor allowing the admission of the pressure fluidinto the front end of said piston chamber to drive said pistonrearwardly, said admission through'said ports being subsequentlyprevented by said stem, an exhaust passage controlledby said pistonthrough which the pressure fluidfrom. both ends of said piston chamberis free to exhaust, and additional exhaust passages controlled by saidvalve through which the atmosphere compressed by the piston inthe rearof said piston chamber is free .to exhaust.

' '2. A. rock drill". comprising a cylinder formed with a pistonchamber, a. piston mounted within said piston chamber, said pistonhaving a stem extending therefrom; a valve block within said cylinderformed with a bore Within which said stem is reciprocably guided, avalve within said valve block having opposed enlarged and restrictedpressure areas subjected to the pressure fluid for shifting and holdingsaid valve in opposite directions, fluid conveying passages opened bysaid valve for allowing the admission of the pressure fluid into one endof said piston chamber to drive said piston in one direction, said fluidconveying passages being subsequently closed by said stem to terminatesaid admission, fluid conveying ports opened by said valve for allowingthe admission of the pressure fluid into the other end of said pistonchamber to drive said piston in the other direction, said admissionthrough said ports being subsequently prevented by said stem, an exhaustpassage controlled by said piston through which the pressure fluid fromboth ends of said piston chamber is free to exhaust, and additionalexhaust passages controlled by said valve through which the atmospherecompressed by the piston in one end of said piston chamber is free to exhaust.

3. A rock drill comprising a cylinder formed with a piston chamber, apiston reciprocably mounted within said piston chamber, said pistonhaving a stem extending therefrom, a valve block formed with a borewithin which said stem is reciprocably guided, a valve reciprocablymounted within said valve block, pressure fluid conveying ports andpassages controlled by said valve and said stem for allowing orpreventing the admission of the pressure fluid into said piston chamberto actuate said piston, said valve being formed with opposed enlargedand restricted pressure area, means for constantly admitting pressurefluid upon said restricted pressure area for shifting and holding saidvalve into one extreme end of its travel, a kick port controlled by saidstem for admitting pressure fluid to said enlarged pressure area toshift said valve into the other extreme end of its travel against theconstant pressure exerted on said restricted area, means for admittingpressure fluid on said enlarged pressure area for holding said valve insaid last mentioned extreme end of its travel, and means within saidstem for allowing the pressure fluid from said enlarged pressure area toexhaust to atmosphere, permitting thereby said valve to shift responsiveto the constant pressure exerted on said restricted pressure area.

4. A rock drill comprising a cylinder formed with a piston chamber, apiston reciprocably mounted within said piston chamber, said pistonhaving a stem extending therefrom, a valve block formed with a borewithin which said stem is reciprocably guided, means for admittingpressure fluid into said bore, a valve re'ciprocably mounted within saidvalve block, pressure fluid con-i veying ports and passages controlledsaid valve and said stem for allowing or preventing the admission of thepressure fluid into said pistonchamber to actuate said piston, Y

an exhaust passage controlled by said piston through which the pressurefluid from said piston chamber is free to exhaust, additional exhaustpassages through which the atmosphere compressed by said piston in oneend of said piston chamber is free to exhaust, said last mentionedpassages being controlled by said valve, opposed enlarged and restrictedpressure areas for said valve, means for constantly admitting pressurefluid on said restricted pressure area for shifting and holding saidvalve in opened position with respect to said additional exhaustpassages, means for intermittently admitting pressure fluid from saidbore to said enlarged pressure area to shift said valve into a closedposition with respect to said additional exhaust passages, and furthermeans controlled by said stem for allowing the pressure fluid from saidenlarged pressure area to exhaust to atmosphere, permitting thereby saidvalve to shift responsive to the constant pressure exerted upon saidrestricted pressure area. 7

In testimony whereof I hereunto affix my signature this sixth day ofSeptember, 1932.

ALBERT FEUGHT.

